First national assessment of wildlife mortality in Ecuador: An effort from citizens and academia to collect roadkill data at country scale

Abstract Ecuador has both high richness and high endemism, which are increasingly threatened by anthropic pressures, including roads. Research evaluating the effects of roads remains scarce, making it difficult to develop mitigation plans. Here, we present the first national assessment of wildlife mortality on roads that allow us to (1) estimate roadkill rates per species, (2) identify affected species and areas, and (3) reveal knowledge gaps. We bring together data from systematic surveys and citizen science efforts to present a dataset with 5010 wildlife roadkill records from 392 species, and we also provide 333 standardized corrected roadkill rates calculated on 242 species. Systematic surveys were reported by ten studies from five Ecuadorian provinces, revealing 242 species with corrected roadkill rates ranging from 0.03 to 171.72 ind./km/year. The highest rates were for the yellow warbler Setophaga petechia in Galapagos (171.72 ind./km/year), the cane toad Rhinella marina in Manabi (110.70 ind./km/year), and the Galapagos lava lizard Microlophus albemarlensis (47.17 ind./km/year). Citizen science and other nonsystematic monitoring provided 1705 roadkill records representing all 24 provinces in Ecuador and 262 identified species. The common opossum Didelphis marsupialis, the Andean white‐eared opossum Didelphis pernigra, and the yellow warbler Setophaga petechia were more commonly reported (250, 104, and 81 individuals, respectively). Across all sources, we found 15 species listed as “Threatened” and six as “Data Deficient” by the IUCN. We recommend stronger research efforts in areas where the mortality of endemic or threatened species could be critical for populations, such as in Galapagos. This first country‐wide assessment of wildlife mortality on Ecuadorian roads represents contributions from academia, members of the public, and government, underlining the value of wider engagement and collaboration. We hope these findings and the compiled dataset will guide sensible driving and sustainable planning of infrastructure in Ecuador and, ultimately, contribute to reduce wildlife mortality on roads.


| INTRODUC TI ON
Ecuador is a small (283,561 km 2 ) but highly biodiverse country hosting two biodiversity hotspots: Choco/Darien/Western Ecuador and Tropical Andes (considered to have the highest richness and endemism of vertebrates species of the planet; Myers et al., 2000).
A recent study estimated that 420,861 birds and 119,599 mammals are roadkilled in Ecuador each year (Medrano-Vizcaíno, Grilo, et al., 2022). The problem is compounded with a further 1555 km of new roads planned by 2030 (MTOP, 2016). With this additional road area, roadkill numbers are predicted to increase by 9.3% K E Y W O R D S biodiversity hotspot, citizen science, Galapagos, road ecology, threatened species, vertebrates
Understanding the effects of roads on wildlife populations is key for conservation plans that include risk assessment, planning of future roads, and mitigation of current impacts. However, conducting systematic roadkill surveys is costly and requires funding for fieldwork, which can be scarce or unavailable in developing countries.
New technology and internet access have provided the opportunity for new ways to gather data with citizens being involved in science projects as active collaborators. Citizen science is a valuable approach that engages diverse people, and offers a way to obtain field data without high costs (e.g., Medrano-Vizcaíno et al., 2020;Mueller et al., 2019). Data on road impacts obtained from citizen science projects can complement systematic surveys. Indeed, several citizen science projects have collected roadkill data and contributed to inform about the magnitude of road impacts on wildlife in different parts of the world (see Chyn et al., 2019;Périquet et al., 2018;Raymond et al., 2021;Swinnen et al., 2022;Valerio et al., 2021). Moreover, involving the public with the collection of roadkill data offers an opportunity to provide environmental education and awareness in local communities (Vercayie & Herremans, 2015), which could significantly contribute to reduce wildlife mortality on roads.
The scarce and disperse information on the ecological impact of roads in Ecuador has limited the potential to identify the areas and species most affected. Lack of information has likely prevented the development of environmental policies and concern of road impacts during the planning of new infrastructures. As a first step to address the knowledge gap, we have consolidated a national database consisting of >5000 roadkill records from systematic studies and nonsystematic observations that represent 392 identified wild species. Analyzing this database, we calculated standardized roadkill rates for data coming from systematic surveys, identified species with high mortality that may require urgent protection measures, and revealed unstudied areas (research gaps) where citizen and scientific efforts are needed to best understand the impacts of roads on Ecuadorian wildlife. Compiling this data required collaboration among citizens and academics. We hope to raise awareness of the issue of road impacts on wildlife in Ecuador and encourage policymakers and researchers to work together to collect needed data to guide conservation plans and sustainable roads.

| ME THODS
Data from systematic studies often control and report sampling efforts, thus allowing us to estimate standardized roadkill rates (i.e., number of individuals killed per area and time span) for different species and areas. However, these studies, and thus their data, are often limited to particular road sections and periods of time. On the other hand, citizen science data (nonsystematic surveys) can cover wider spatial and temporal windows, but sampling is often not systematized or quantified, which makes the definition of standardized estimates complicated. To avoid methodological issues, data obtained from these two approaches are presented separately.

| Records from systematic studies
We completed a comprehensive search for roadkill surveys conducted in Ecuador, considering only peer-reviewed publications and BSc, MSc, or PhD theses that reported data on the length of road surveyed, taxonomic information of roadkilled species, number of roadkills per species, and survey period. The bibliographic search was performed between March and May 2022 using Google Scholar, Scopus, Web of Science, and PubMed Advanced Search Builder (ASB) with keywords in English and Spanish. The use of both languages was necessary given that Ecuador is a Spanish-speaking country, and some studies may be published in that language. No time limit was set for the search, if they met the required eligibility criteria, all publications irrespective of date were included. We used the following search strings: Search 1: "Ecuador*" AND ("roadkill*" OR "wildlife mortality" OR "wildlife-vehicle collision*" OR "wildlife vehicle collision*") AND ("animal*" OR "amphibian*" OR "bird*" OR "avian*" OR "mammal*" OR "reptile*" OR "snake*" OR "frog*"). Search 2: "Ecuador*" AND ("atropellamiento*" OR "colisión" OR "colision*") AND ("animal*" OR "fauna" OR "vida silvestre" OR "silvestre*" OR "anfibio*" OR "ave*" OR "pájaro*" OR "mamífero*" OR "reptil*" OR "serpiente*" OR "culebra*" OR "sapo*" OR "rana*"). The authors were contacted for those publications that did not disclose the original dataset; otherwise, the published dataset was downloaded and processed. From each found dataset, we collected data on the following variables: taxonomic identification of roadkilled organisms, number of roadkills per species or lowest identified taxonomic group, length of road surveyed, survey method (e.g., car, motorcycle, bicycle, or walking), time interval between surveys, date of survey, total sampling period, and geographical coordinates of each roadkill record when available. As original records could include synonyms or obsolete species names, we standardized taxonomic names with the IUCN nomenclature. We removed any records of domestic and farm animals. For each dataset, we calculated roadkill rates per species (only specimens identified to species were considered) by dividing the total number of records by the total length in kilometers of the surveyed road(s) and the total sampling period (i.e., number of days between the first day until the last day of fieldwork). The obtained values were transformed into standardized roadkill rates as the number of individuals per km per year multiplying by 365. Additionally, as detectability and survey intervals can influence the number of individuals detected as roadkill, we applied some correction factors.
Roadkill rates were multiplied by correction factors based on taxonomic groups, body mass, and survey intervals, proposed by Santos et al. (2011). Additionally, as surveying roads by driving a car could result in a lower carcass detectability, roadkill rates were also multiplied by correction factors proposed by Wang et al. (2022). A full list of these correction factors is provided in Supporting Information Appendix S1. Standardized corrected roadkill rates allow for better comparison of road mortality among species and areas where systematic studies have been conducted.

| Citizen science and other records (nonsystematic monitoring)
Our main data source was our citizen science project, entitled "Red Ecuatoriana para el Monitoreo de Fauna Atropellada" (REMFA) (remfa.webno de.co.uk), which started in September 2020 and is ongoing. For the present analysis, we used records reported in the first 24 months (September 2020-2022) of REMFA's activity.
REMFA is an initiative that, in addition to capturing roadkill data, seeks to promote citizen environmental education on road ecology. Using word of mouth as well as traditional and social media, we Rangers from Parque Nacional Cayambe Coca zona baja also provided a previously compiled database of nonsystematic roadkill observations. Additionally, we included sporadic roadkill records found in the scientific literature but that had not been gathered via systematic surveys.
As several records are reported by nonbiologist citizens, misidentifications, or the use of common names are usual. Therefore, the REMFA team (biologists, taxonomists, and database manager) curated all records individually, confirming, correcting, or determining species identification (analyzing photographs provided with each record). When photographs or the deteriorated state of carcasses did not allow species identification, we assigned less specific taxonomic identification (e.g., genus, family, order, class). We checked for consistency of geographical data provided by users using Geographical Information Systems and known distribution areas of species consulting specialized literature (e.g., Ridgely & Greenfield, 2006;Tirira, 2017;Valencia et al., 2016) and IUCN and BIOWEB web platforms (IUCN, 2022;Pontificia Universidad Católica del Ecuador, 2021).
Inconsistent data were removed.
In contrast to systematic monitoring, nonsystematic monitoring lacks standardized methodologies, and sampling effort is largely unreported, therefore estimating roadkill rates was not possible.
Accounting for these limitations, we summarize data from nonsystematic studies by reporting the total number of records for identified taxonomic classes and species (when identified), and totals for each Ecuadorian province.
For systematic and nonsystematic data, when geographical coordinates of roadkill events were not available, we defined coordinates as the central point of the geographical reference provided by citizens or the published source. For these cases, we included an uncertainty value to account for the potential error in the estimated coordinates based on the described area or road. This was given in km when we had information on the location of the road where the roadkill was found, or in km 2 when the road was not described, but we had information on the administrative area.

| RE SULTS
We compiled a total of 5010 roadkill events from both systematic and nonsystematic surveys (citizen science and other studies were the fourth and fifth most roadkilled species, respectively.

| Systematic studies
We   (IUCN, 2022), six species were found in a category of conservation concern, and two as Data Deficient (

| Citizen science and other records
Citizen science and other nonsystematic records provided a smaller sample of 1705 roadkill records but offered a much wider geographical coverage than the systematic data with records from all 24 provinces of Ecuador (Figure 2 Coragyps atratus from eight provinces. As with the systematic data, most records represented species classified as Least Concern by the IUCN Red List (IUCN, 2022), but there were 12 species of conservation concern, four currently listed as Data Deficient, and one not yet assessed by the IUCN (Table 5).

| DISCUSS ION
We compiled a large dataset that describes mortality due to wildlifevehicle collision in Ecuador based on both systematic surveys and nonsystematic records that came from citizen science and opportunistic observations reported in the scientific literature. Collectively, these data reveal that 11.79% of described vertebrate species from Ecuador are susceptible to die on roads, a number that likely underestimates the true impact of roads as not all individuals could be identified at the species level, not all areas are well sampled, and smaller and cryptic species may be underreported. We see a need for additional systematic surveys, which can provide more comparable estimates but so far have been few and limited to some areas.
Likewise, citizen science reports are overrepresenting certain areas, with gaps in other regions.
We found that marsupials (D. marsupialis and D. pernigra) repre- Among the systematic studies, we estimated particularly high standardized roadkill rates in some cases. Studies in Galapagos , Napo (Filius et al., 2020), and Manabi (Gaón & Valdez, 2021) reported roadkill rates that were disproportionally high in comparison with other studies and were all conducted in small areas (13.8, 15.8, and 10 km, respectively). These areas could be hotspots of mortality that do not represent rates across wider areas (overestimate risk), nevertheless, how road impacts wildlife in areas of biological importance should be further studied.
For example, high road mortality for endemics of the Galapagos Islands could threaten population persistence (Tejera et al., 2018;Wiedenfeld, 2006). In this territory, threatened species comprise 20 out of 43 bird species, 18 out of 42 reptile species, and 6 out of 9 noncetacean mammals species (IUCN, 2022), for which the impacts of roads on their populations remain unexplored but also nonthreatened species may be impacted. For example, the yellow warbler, Setophaga petechia, that was commonly reported as roadkill, has experienced a dramatic population decline, and although low insect abundance due to intense use of herbicides has been associated with this decline (Dvorak et al., 2012), road mortality  Note: We present taxonomic information (class, order, and species), IUCN Red List status, number of studies in which the species was recorded, estimated standardized corrected roadkill rate (if a species was detected in more than one study, we report its highest rate), and the province for the reported rate.
TA B L E 3 Species listed as threatened or data deficient by the IUCN Red List or not yet unassessed, which were reported as roadkill by systematic surveys in Ecuador. Note: We provide taxonomic information (class, order, and species name), IUCN Red List status, the number of studies in which that species was recorded, the estimated corrected roadkill rate (if a species was detected in more than one study, we report its highest corrected rate), and the province for the reported rate.

F I G U R E 2
Location of all roadkill records compiled from citizen science and other sources and total number of records for each taxonomic Class and province Additionally, poorly-studied organisms such as Caecilians and Atractus sp. snakes were also regularly reported as roadkill. These animals are among the least known vertebrates, with several taxonomic uncertainties and unknown conservation status for many of them (Cisneros-Heredia, 2005;IUCN, 2022;Wilkinson, 2012).
Both groups were frequently detected across three studies in Napo (Filius et al., 2020;Medrano-Vizcaíno, Brito-Zapata, & González-Suárez, 2022;Medrano-Vizcaíno & Espinosa, 2021), and nonsystematic data included 41 records of Atractus sp. snakes. In a survey conducted in 2014, Medrano-Vizcaíno and Espinosa (2021) found two roadkilled individuals attributed to the genus Atractus in Napo, which were latter described as new species (described by Melo-Sampaio et al., 2021;Arteaga et al., 2022). Road ecology research in areas with poorly known and undescribed species would be valuable, both to quantify impacts but also to strengthen our understanding of these species.
Our study offers an overview of wildlife mortality on Ecuadorian roads but likely underestimates the impact of roads on species.
We obtained roadkill records from all 24 provinces in Ecuador, but systematic studies were only available for five, and nonsystematic data were disproportionally distributed in provinces like Manabi, and Napo (more than 300 records for each province  Brito-Zapata, 2021). Roadkill records can provide valuable information about the biology and ecology of species, and with correct taxonomic identification, can contribute to our understanding of biodiversity.
Road ecology research in Ecuador is gaining interest, but it is still relatively limited. Promoting and guiding additional research and public engagement is important. Through our citizen science project REMFA we have given a special relevance to science communication, which has been vital to reach citizens to join our work, and we are now engaging with policymakers. The active involvement of government institutions such as the Ministry of Environment, Water and Ecological Transition, together with the Ministry of Public Works is necessary for the inclusion of adequate policies to reduce wildlife mortality across existing roads, and to plan sustainable roads for the future. We hope that this work can be an initial step towards these national aims for wildlife conservation.